1. Technical Field
Photoresist monomers, polymers thereof and photoresist compositions containing the same are disclosed. In particular, photoresist monomers suitable for a photolithography process using DUV (deep ultraviolet) light sources such as VUV (157 nm) and EUV (13 nm) in fabricating a minute circuit for a high integration semiconductor device, photoresist polymers thereof and photoresist compositions containing the same, and preparation processes therefore are disclosed.
2. Description of the Prior Art
In general, a useful photoresist for VUV has a variety of desired characteristics, such as low light absorbance at the wavelength of 157 nm, excellent etching resistance, and excellent adhesiveness to a wafer. In addition, a photoresist should be easily developable in a commercially readily available developing solution, such as 2.38 wt % and 2.6 wt % aqueous tetramethylammonium hydroxide (TMAH) solution.
Recently, there has been much research done on resins having a high transparency at the wavelength of 193 nm and dry etching resistance similar to novolac resin. However, most of the photoresists are not suitable for VUV due to their poor transmittance at 157 nm wavelength.
Photoresists containing fluorine and silicon have good transmittance at these wavelengths. Unfortunately, most photoresists containing fluorine with a polyethylene or polyacrylate polymer backbone have weak etching resistance, low solubility in an aqueous TMAH solution and poor adhesiveness to the silicon wafer.
On the other hand, photoresists containing silicon require a 2-step etching process of HF treatment and O2 treatment. And it is difficult to remove HF completely, which makes these types of photoresists unsuitable to be applied into production.
However, polyethylene or polyacrylate resins comprising fluorine having excellent solubility have been recently developed. Nevertheless, such resins have low adhesiveness to a wafer, low etching resistance and high light absorbance for applying to resist.
Novel photoresist monomers and polymers thereof that can be used for a light sources such as VUV (157 nm) and EUV (13 nm) are disclosed.
A photoresist composition comprising the photoresist polymer described above is also disclosed.
A semiconductor element produced by using the photoresist composition described above.